I. Field Of The Invention
The present invention relates to closure valves for toilet tanks and more particularly relates to a buoyancy rate adjustable flapper valve which reduces the volume of flushing water required.
II. Description Of The Prior Art
Conventional toilets include a water tank and a bowl. The toilet tank includes a ball valve which is raised from the tank discharge outlet to allow water to be discharged from the tank into the bowl. As the water level in the tank drops, the ball valve will drop into sealing engagement with the water discharge outlet. The water fill valve is usually actuated when the ball valve is lifted to introduce water into the tank. When the valve re-seals the discharge outlet, fill water will continue to flow into the tank until it rises to a predetermined level at which time it shuts off.
The prior art is replete with various structures and configurations of ball valves or other types of tank discharge valves. Many of these valves are designed to provide a flush of reduced water volume in order to conserve water. One type of water saving valve known as a flapper type valve is designed to allow water to flow to the interior of the flapper to increase its weight. By increasing the weight of the valve at a rate more rapidly than the reduction in the water level in the toilet tank, early closure of the valve can be effected prior to complete discharge of the water from the toilet tank or reservoir. By controlling the rate of valve weight increase, the tank water level at which the valve will seal the discharge outlet can be predetermined.
Some prior art patents suggest controlling the weight increase of the flapper valve by regulating the air bleed rate. This approach is usually only minimally effective since the air bleed must be of relatively small size and may become partially clogged due to the presence of minerals and debris in the water. It has been found that control of the closure rate by regulating the flow of the water inflow rate is generally more effective since water is incompressible and more easily controlled.
The following patents are representative and show adjustable tank discharge valves. For example, U.S. Pat. No. 4,419,773 discloses a discharge valve closure of the type which has a bleeder port to permit the conservation of water by causing the closer to shut the discharge valve prior to draining all the water from the tank. The discharge valve closure features an adjustment which permits at least a portion of the buoyancy chamber to be pivoted about the axis of the closure to position the bleeder port at a selected angular spacing from its top dead center. This adjustment allows the tank water level at which the closure shuts off the discharge valve to be adjusted.
U.S. Pat. No. 4,935,598 discloses a toilet tank flapper valve providing user selection of either a full or partial dispensing of the contents of the tank. A ball check valve located in the flapper either obstructs water from entering or permits it to enter the buoyancy chamber of the flapper valve. When water is permitted to enter a partial dispensing action results.
U.S. Pat. No. 4,189,795 commonly assigned with the present application discloses an improved ball valve for a toilet tank flush tanks for regulating the quantity of water released from the tank in the flush and includes a gauged or adjustable water inlet hole at the bottom of file ball valve and an air bleed hole at the top of the ball valve. The water inlet hole at the bottom of the ball valve is adjustable in size for selectively setting the flow of water entering the ball valve during a flush action and thereby determining the time the ball valve remains open to allow flush water to drain from the tank.
Other patents show toilet tank valves which permit inflow of water to achieve negative buoyancy at a predetermined point prior to complete discharge of the water from within the toilet tank can be found in the following patents: U.S. Pat. Nos. 2,511,545; 2,598,967; 2,741,775; 2,752,608; 2,830,302; 2,852,783; 2,869,141; 2,962,727; 3,086,218; 3,320,622; 3,5:46,715; 3,590,395.